1. Field of the Invention
This invention relates to Hookes universal joints, of the type which comprises two joint yokes rotatable about respective axes of rotation and connected together by a cross-member, each yoke comprising two spaced arms extending generally parallel to the rotational axis of the yoke, the arms being connected together at their one ends and provided adjacent their other, free, ends with bores having axes aligned with one another and extending perpendicular to the rotational axis of the yoke for receiving bearing bushes supporting an opposed pair of journals of the cross-member, each yoke arm comprising a main part and a removable portion connected to the main part of the arm in the region of the bore but offset from the bore axis towards the free end of the arm. Such a joint will hereafter be referred to as a Hookes universal joint of the kind specified.
In a Hookes universal joint of the kind specified, part of the circumferential surface of the bore in each yoke arm is provided on the removable portion of the arm. Removal of the portion leaves an opening into the bore, enabling the cross-member of the joint more easily to be positioned relative to the yoke such that its opposed journals lie within the bores in the yoke arms. The removed portions of the yoke arms can then be refitted thereto, and the bearing bushes fitted in the bores in the usual way, i.e. by inserting them radially inwardly towards the rotational axis of the yoke, along the axes of the bores in which they are received. This method of assembly is necessary in case the dimensions of the yoke arms and the cross-member are such that the cross member could not be maneuvered to fit its journals in the bores in the yoke arms if the yoke arms did not have their removable end portions.
2. Description of Prior Art
It has been proposed in German Patent Specification No. 3209658 to provide the removable portion of each yoke arm with projections which engage into corresponding recesses in the main part of the arm. The recesses have slightly conical faces, disposed about production axes offset from but parallel to the bore axis, and the removable portion is fitted by movement in the direction parallel to the bore axis. The removable portion is held to the main part of the yoke arm by bolts. However, the form fitting connection between the projections and recesses extends over only part of the thickness of the yoke arm, and the region in which the removable portion is connected to the main part of the arm is weakened by the necessity of providing holes for the securing bolts.
In addition to the disadvantage of the weakening effect of the holes for the securing bolts, there is a risk of the yoke arms undergoing uneven deformation under high torques, and the bearing bushes are not being adequately supported by the yoke arms.